Process of masticating rubber and product thereof



United States Patent O 3,004,944 PROCESS OF MASTICATING RUBBER ANDPRODUCT THEREOF Theo Kempermann, Koln-Lindenthal, Friedrich Lober,

Leverkusen-Bayerwerk, and Helmut Klappcrt, Koln- 5 This inventionrelates to novel masticating agents for natural and synthetic rubber.

The natural rubber supplied by the plantations is generally too hard andelastic for it to be mixed directly with fillers, sulfur, acceleratorsand other rubber auxiliary products and then further processed to formthe required rubber articles. The same conditions apply as regardsstandardised synthetic rubber types, for example copoly mers ofbutadiene and styrene, butadiene and acrylonitrile and other rubber-likecopolymers. It is consequently necessary to masticate it prior to themixing process, i.e. to make it plastic. The mastication can be carriedout purely mechanically without the addition of chemical auxiliaries byworking on the roller or in a kneading machine. This process, which mustbe carried out at a low temperature, generally takes a relatively longtime, however. For better exploitation of the existing processingcapacities in the plant, and for saving energy, masticating agents aregenerally added and the mastication takes place at higher temperatures.In this way, a very rapid and uniform breakdown of the rubber isobtained.

Examples of conventional masticating agents are thiophenols which can bedifferently substituted in the aryl radical, and also their disulfidesand zinc salts. Nitroso compounds and hydrazine derivatives have alsobeen used as plasticizers. very effective even in small proportions, butthat on the other hand it is necessary for the concentrations of plasticizers not to fall below a certain minimum. For example, the limit ofefficacy for zinc pentachlorothiophenol in the It is known that thesecompounds are ICE heterocyclic rings, whereby said heterocyclic ringscan contain for example nitrogen or sulfur:

Examples of these compounds are the tetraazaporphins.

. The compounds always contain metals, such as iron, co-

balt, nickel, chromium, manganese, zinc, aluminum, vanadium ormagnesium, for example, which are combined in complex form. Eiiectivemetal complexes of the said type are for example obtained fromunsubstituted or substituted amino pyrrolenines, such as for exampleaminoimino-isoindolenines or from maleic acid or maleic acidderivatives, with guanazole (3,5-diamino-triazole-(1,2,4))

or substituted guanazoles and metal salts.

The masticating agents are used in the conventional manner, e.g. byadding these compounds to the natural or synthetic rubber to bemasticated on a roller or a conventional mastication of natural rubberat 130 is in the range from 0.1 to 0.15%, calculated on the rubber.Below this concentration, the mastication proceeds so slowly that theprocedure becomes uneconomic.

It has now been found that metalcontaining compounds 7 kneader andmasticating this mixture at elevated temperature. It is, however,advantageous to employ them in admixture with inert fillers, since theycan otherwise be only unsatisfactorily and incompletely dispersed in therubber, on account of the very low proportion used. It is generallyadvisable to select a ratio of 1:50 to 1:500

between the weights of masticating agent and filler.

Suitable fillers are e.g. kaolin, bleaching earth, siliceous chalk,highly dispersed silica and silicates, such as usually employed in theprocessing of rubber.

atom, are likewise suitable as masticating agents for natural orsynthetic rubber.

Generally speaking, it is desirable for the masticating agents usedinaccordancewith the invention to be employed in proportions of 0.00001 to0.1%, preferably 0.0001 to 0.01% by weight, calculated on the rubber,for

mastication purposes, and for the operation to be carried out attemperatures between 60 and 200 C. v The following formulae indicateexamples of the macrocyclic compounds used in accordance with theinvention,

in which formula Me represents a metal atom which is at least divalentand each R represents in accordance with the aboveidefinition of thecompounds of the invention an organic radical, such as for example analkyl, such as methyl, ethyl or propyl, aryl or cycloalkyl radical,pairs halogen, alkyl, alkoxy or nitro groups, carbocyclic or of whichcanform unsubstituted or substituted, e.g. by

The compounds employed in accordance with the invention develop theirefiect independently of other additives. It is consequently possible toefiect mastication without the addition of any other known masticatingagent. If it is desired, there can be used mixtures of masticatingagents also with other known masticating agents such as for examplepentachlorothiophenol or its zinc salt and the compounds hereinbeforedescribed, possibly with the further addition of inert fillers. If it isdesired, e.g. to keep the concentration of the metal-containingmacrocyclic compounds as small as possible then there can be added forexample a suitable masticating agent of the thiophenol type, for examplezinc pentachlorothiophenol or pentachlorothiophenoh This mixture givesthe same efiicacy as with a higher concentration of the metal complexalone. The proportion of conventional masticating agents then necessaryis substantially smaller than when the metal complex is not present.

The ageing properties of vulcanizates of rubber which has beenmasticatedwith the previously described complex compounds, possibly in combinationwith known masticating agents are exce1lent and do not differ in any wayfromthose of vulcaniiates which have been produced 5 Compound C:

from a rubber which has been-masticated exclusively with 7 N p 7 knownchemical masticating agents. The metal com- OCH3 bined in complex formin the complex compounds used in accordance with the invention thereforedoes not cause any additional breakdown in'the vulcanizate under the 10usual ageing conditions.

The following examples shows the action of the compounds in accordancewith the invention; both in cases where they are mixed only with inertfillers and also in 7 cases where they are combined with knownmasticating agents. In the tables of these examples the 1. number in-01130 dicates the Defo values according to DIN 53514 and the 2. numberthe Defo elasticity. The amounts used are percent by weight of nototherwise indicated. Furthermore, the following tetraazaphorphins orhemio h razines are desi nated b the letters A--D: D ID y g y CompoundD:-

Compound A:

Q Q N N c N c i n i so C-N I 0 l u i II N Fe N Fe N 11 & II l C--N N--t;J--N NC I l L l H 7 EXAMPLE 1 Masticatian of smoked sheets at 130 C.in a 2-liter kneader Mastlcating agent Without addition; Zincpentachloro- Blend-Kaolin Blend-Kaolin Blend-Zinc Blend-Zinc t V tthlophenol 99.25% Oom- 99.7% Compentachlnropentachloro- (100%). pound A0.75%. pound A 0.3%. thlophenol 33%, thiophenol 33%,

Kaolin 66.9%, Kaolin 67%. t g inpound A Proportion in percent 0.2:: 0.250.25 0.25'- 0.25.

(car 0. on rubber). 7 Data values after- 0min 23001221 2.2001102 moo 2 a2300/22; 2200/22; 2,200/32.3. ,4 mln -.V l,750/37.7 525/181 475/ 1625115.? 550/ a 1.10o/25.0. 9min 1,400/25.7 250mm 230/8.7 zen/ran325/16.7 son 20.7. 12 min 1,175 21 n 180/12 0 110/6.7 17mm 0 230/18 0675/190 1 min nan 9n a 1mm 2 /61 110/7 2 170/11 0 600/17 3.

Compound B: v V

EXAMPLE 2 OH: N J; Mastication of smoked sheets at 130 C. in a 2-11"!Izn ader CAGE; o5 er e N-C I ll Fe N Mmleatingsgent....---.-.-.. Withoutaddition. Blend-Kaolin l A} 69.7%, Corn- N N- poundB 0.3%. .5 [1Proportion in percent (calc. 0.25. GHa-C NC N 10 Do? ruhber e V3 U658er- G N 0 min. 235mm 1 2.3501363. L 4 mm. 1.800110 2 950/250. H, 8 min.1,500/27 a 715/230. 12 mm 1,300/250 650/193. 16 min- 1,!/22J GOO/19.3.

EXAM PLE s w Mastication of smoked sheets at 130 C. in a 2-liter kneaderMasticating agent. Without addl- Blend- Blendtion. glfa pin ga pln JCompound Compound 0.3%. 3%. Proportion in percent (calc. on rubber).Deio values alter- EXAMPLE 4 Mastication of butyl rubber (1.5 molpercent isoprene) in a 2-liter kneader at 130 C. rubber temperaturemasticating agent".-- Without addi- Zinc penta- Zinc pentatlon.chlorothiochlorothiophenol phenol 33.0%, 100.0%. as Comiiound A 0.1%.Proportion in percent 0.3 0.3. Date values afterl,l50/22.3 1.1501223LEO/22.3.

EXAMPLE Mastication of smoked sheets at 130 C. in a 2-liter kneaderMasticating agent"-.. Without addition. Blend-Kaolin 99.7%,

Compound E 0.3%. Proportion in percent- 0.25.

Dem values aitersac 15.3.

Compound E was obtained by heating: 9 g. of 1-phenyl-3,5-diaminotriazol-l,2,4, 15 g. of 1-amino-3-iminoisoindolenineand 5 g. of iron-lI-chloride in 150 ml. of glycol for. 8 hours to 100l10C. Upon diluting the mixture with methanol the reaction product isfiltered off and washed with methanol and water. Yield: 14

grams.

We claim:

1. Process for the mastication of a member selected from the groupconsisting of natural rubber, rubbery diolefin homopolymers, and rubberycopolymers of diolefins and monoolefins which comprises masticating thesame in the presence of metal-containing compounds which have alfi-membered macrocyclic ring system in which 8 carbon atoms and 8nitrogen atoms are arranged alternatively and in which each secondnitrogen atom forms a heterocyclic ring with the two adjacent carbonatoms by means of a linkage selected from one of the followinggroupings:

wherein X and Y represent a lower alkyl radical and Z is selected fromthe group consisting of hydrogen, phenyl,

lower alkoxy, halogem'and alkyl radicals and wherein i116 gIOu Q I iscontained at least once in the molecule.

2. Process as claimed in claim 1, wherein the compounds are used inadmixture with other masticating agents.

3. Process as claimed in claim 1, wherein the following compound is usedas masticating agent:

4. Process as claimed in claim 1, wherein the following compound is usedas masticating agent:

wherein X and Y represent a lower alkyl radical and Z is selected fromthe group consisting of hydrogen, phenyl, lower alkoxy, halogen, andalkyl radicals and wherein the p b is contained at least once in themolecul.

6. Process of claim 1 wherein the polymer is natural rubber.

7. Process of claim 1 wherein the polymer is a copolymer of isobuteneand isoprene.

Q, Process of claim 1 wherein the is a compound of the formulamasticating agent GHaO 9. Process of claim 1 wherein the masticatingagent is a compound of the formula I '10. A process for the masticationof natural rubber which comprises masticating said natural rubber in thepresence of the masticating agent of claim 3.

11. A process for the mastication of natural rubber which comprisesmasticating said natural rubber in the presence of the masticating agentof claim 4.

12. Process for the mastication of a member selected 7 from the groupconsisting of natural rubber, rubbery diolefin homopolymers, and rubberycopolymers of diolefins and monoolefins which comprises masticating thesame in the presence of metal-containing compounds which have aIG-meinbredmacrocyclic ring system in which 8 carbon atoms and 8nitrogen atoms arearranged alternatively and in which each secondnitrogen atom forms a heterocyclic ring with the two adjacent carbonatoms by means of a linkage selected from one of' the followinggroupings:

wherein X and Y represent a lower alkyl radical and Z is selected fromthe group consisting of hydrogen, phenyl, lower alkoxy, halogen, and'alkyl radicals and wherein polyrner of isobutene and isoprene.

15. Process for the mastication of a memberselected from the groupconsisting of natural rubber, rubbery diolefin homopolymers, and rubberycopolymers of diolefins and monoolefins which comprises masticating thesame in the presence of metal-containing compounds 7 which have a16-membered macrocyclic ring system in which 8 carbon atoms and 8nitrogen atoms are arranged alternatively and in which each secondnitrogen atom forms a heterocyclic ring with the two, adjacent carbonatoms by means of a linkage selected from one of the followinggroupings:

wherein X and Y represent a lower alkyl radical and Z is selected fromthe group consisting of hydrogen, phenyl, lower alkoxy, halogen,andjalkyllradicals and wherein the grouping is contained at least oncein the molecule.

16. Process of claim 15 wherein the rubber being masticated is naturalrubber.

17. Process of claim' 15 wherein the rubber is a copolymer of isobuteneand isoprfene'."

References Cited in the file of this patent UNITED STATES PATENTS1,860,116 Pikl Nov. 11, 1958

1. PROCESS FOR THE MASTICATION OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF NATURAL RUBBER, RUBBERY DIOLEFIN HOMOPOLYMERS, AND RUBBERY COPOLYMERS OF DIOLEFINS AND MONOOLEFINS WHICH COMPRISES MASTICATING THE SAME IN THE PRESENCE OF METAL-CONTAINING COMPOUNDS WHICH HAVE A 16-MEMBERED MACROCYCLIC RING SYSTEM IN WHICH 8 CARBON ATOMS AND 8 NITROGEN ATOMS ARE ARRANGED ALTERNATIVELY AND IN WHICH EACH SECOND NITROGEN ATOM FORMS A HETEROCYCLIC RING WITH THE TWO ADJACENT CARBON ATOMS BY MEANS OF A LINKAGE SELECTED FROM ONE OF THE FOLLOWING GROUPINGS: 